Which of the following is the correct way to find the number of neutrons in an element? A. add protons and neutrons

B. subtract atomic mass from atomic number

C. subtract atomic number from atomic mass

D. add atomic mass and atomic number

The Answer is B: subtract atomic mass from atomic number. I remember doing this in 8th grade!!!:)

Explanation:

The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom is equal to the sum of the number of protons and neutrons in the nucleus. The number of neutrons is equal to the difference between the mass number of the atom and the atomic number.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.